Explore the history of DNA on this interactive timeline. Discover key moments in the study of DNA as well as more recent developments in DNA technology, such as genetically engineered food and cloning.
Test your knowledge about setting, characters, sequence, exposition, conflict, climax and resolution. Take this 14-question test, review your correct and incorrect answers, and print out your assessment.
Try to meet the world's projected energy demand by choosing from the available energy sources, while keeping atmospheric CO2 under control. You must avoid the limits and pitfalls associated with each energy source.
One way to solve a complicated problem is to solve a smaller version of the same problem. Without working out the larger problem, predict how many sheep will get shorn before impatient Eric, who is sneaking up in line little by little.
Use molecular information and observe female response patterns to learn about the mating calls of Physalaemus frogs. Examine the evolution of female preference for particular call characteristics. View non-Flash version.